Conway does make specific recommendations for whitespace and curly-braces in your code,
but the most important thing is to adopt a consistent layout,
regardless of the specifics.
And the easiest way to do that is to use Perl::Tidy.
This policy will complain if you're code hasn't been run through Perl::Tidy.

This policy can be configured to tell Perl::Tidy to use a particular perltidyrc file or no configuration at all.
By default,
Perl::Tidy is told to look in its default location for configuration.
Perl::Critic can be told to tell Perl::Tidy to use a specific configuration file by putting an entry in a .perlcriticrc file like this:

[CodeLayout::RequireTidyCode]
perltidyrc = /usr/share/perltidy.conf

As a special case, setting perltidyrc to the empty string tells Perl::Tidy not to load any configuration file at all and just use Perl::Tidy's own default style.